Synthesis, spectroscopic, thermal and antimicrobial studies of toluene-3,4-dithiolatoarsenic(III) derivatives with some oxygen and sulphur donor ligands

Article abstract of DOI:10.1016/j.saa.2012.07.086

Replacement reactions of toluene-3,4-dithiolatoarsenic(III) chloride with oxygen and sulphur donor ligands like benzoic acid, thiobenzoic acid, anhydrous sodium acetate, thioacetic acid, phenol, thiophenol, sodium salicylate and thio glycolic acid in 1:1

Full text of DOI:10.1016/j.saa.2012.07.086

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
Contents lists available at SciVerse ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Synthesis, spectroscopic, thermal and antimicrobial studies of
toluene-3,4-dithiolatoarsenic(III) derivatives with some oxygen and
sulphur donor ligands
⇑
H.P.S. Chauhan , Sumit Bhatiya
School of Chemical Sciences, Devi Ahilya University, Takshashila Campus, Khandwa Road, Indore 452 001, India
g r a p h i c a l a b s t r a c t
h i g h l i g h t s
"
Toluene-3,4-dithiolatoarsenic(III)
compounds have been synthesized.
Spectral studies consist of UV, IR,
NMR, ESI mass, SEM, powder XRD
and thermal studies.
"
"
"
"
Powder XRD exhibited two phase
and nanocrystalline structure of
compounds.
Complexes showed good
antimicrobial activity against
bacteria and fungi.
These studies provided structural,
thermal and biological importance of
As compound.
. . O
S
As
S
S
H C
3
a r t i c l e i n f o
a b s t r a c t
Article history:
Replacement reactions of toluene-3,4-dithiolatoarsenic(III) chloride with oxygen and sulphur donor
ligands like benzoic acid, thiobenzoic acid, anhydrous sodium acetate, thioacetic acid, phenol,
thiophenol, sodium salicylate and thio glycolic acid in 1:1 molar ratio as well as disodium oxalate
in 2:1 molar ratio in refluxing anhydrous benzene yielded toluene-3,4-dithiolatoarsenic(III) mono
oxo or thio carboxylic or phenolic derivatives of the general formula SC6H3(CH3)SAsR {where
R = OOCC6H5, SOCC6H5, OOCCH3, SOCCH3, OC6H5, SC6H5, OOCC6H4(OH), SCH2COOH} and SC6H3(CH3)-
SAsOOC-COOAsS(CH3)C6H3S.
These synthesized derivatives are yellow, yellow-brown solids/ liquids and are soluble in common
organic solvents like benzene, chloroform, dichloromethane, dimethyl formamide, dimethyl sulphoxide
etc. These derivatives have been characterized by melting point determination, molecular weight
determination, elemental analysis (C, H, S and As), spectral {UV, IR, NMR (1H and 13C), ESI-Mass,
SEM and powder X-ray diffraction} and thermal (TGA, DTA and DSC) studies. Some of these com-
pounds have been screened for their antimicrobial activities using the disc diffusion method. These
derivatives have shown good activity as antibacterial and antifungal agents on some selected bacterial
and fungal strains, which increased on increasing the concentration. Chloroamphenicol and terbinafin
were used as standards for the comparison.
Received 26 March 2012
Received in revised form 23 June 2012
Accepted 5 July 2012
Available online 3 August 2012
Keywords:
Toluene-3,4-dithiolatoarsenic(III)
derivatives
1H and 13C NMR
ESI-Mass
SEM and Powder XRD
TGA, DTA and DSC
Antimicrobial Studies
Ó 2012 Elsevier B.V. All rights reserved.
⇑
Corresponding author. Tel.: +91 0731 2365948, +91 0731 2460208; fax: +91 0731 2365782.
E-mail addresses: hpsc@rediffmail.com (H.P.S. Chauhan), sumit.bhatiya@ gmail.com (S. Bhatiya).
1386-1425/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.saa.2012.07.086

1134
H.P.S. Chauhan, S. Bhatiya / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
75.45 MHz for 1H and 13C NMR, respectively. The ESI-Mass spectra
Introduction
were recorded with a Waters Micromass Q-Tof Micro Mass Spec-
trometer, which is coupled with Waters 2795 HPLC having quater-
nary pumping configured for flow rates from 0.05–5.0 ml/Min.
Powder X-ray diffraction studies were performed on diffractome-
ter system XPERT-PRO using CuK radiation at a wavelength of
Arsenic dithiolates complexes of oxygen and sulphur containing
ligands largely gain attraction due to their structural characteris-
tics and applicability in various fields. These complexes also exhib-
ited various biological applications and thermal properties. The
1,1-dithiolato ligands {like dialkyldithiocarbamates [1,2], dial-
kyldithiophosphate [3,4], alkylenedithiophosphate [5,6], xanthates
[7,8]}, 1,2-dithiolato ligands {like 1,2-ethanedithiol [9–11], tolu-
ene-3,4-dithiol [12,13]} and carboxylic ligands [14,15] are versatile
in nature and exhibit remarkable diversities in their bonding/
coordination possibilities with main group metals. Now organoar-
senical compounds are being trialed for the treatment of hemato-
logical malignancies and solid tumors [16,17]. Arsenic thiolates
have been of interest since World War II with the treatment of
Lewisite poisoning (Cl2AsCH@CHCl) with the dithiol-2,3-dimercap-
topropanol more commonly known as British Anti-Lewisite (BAL)
[18]. Recent interest in arsenic thiolates as building blocks in
self-assembled macrocycles [19,20] along with a lack of single
crystal X-ray structural analysis of relatively arsenic thiolates has
prompted our work on the synthesis and characterization of
arsenic dithiolates [12,21], now we report herein the synthesis,
spectral, thermal and antimicrobial studies of some toluene-
3,4-dithiolatoarsenic(III) oxo and thio carboxylic and phenolic
compounds of the general formula SC6H3(CH3)SAsR [where
R = OOCC6H5, SOCC6H5, OOCCH3, SOCCH3, OC6H5, SC6H5, OOC-
C6H4(OH), SCH2COOH and 1/2 OOC–COO].
a
0
1.54 ÅA. The TGA, DTA and DSC analysis were carried out in inert
atmosphere. For the TGA and DTA studies, a Mettler Toledo, model:
TGA/SDTA 851e and for the DSC studies, Mettler Toledo, model:
DSC 822e instruments, were used and SEM studies performed on
a Jeol JSM 5600 having magnification range 92,500ꢀ10
accelerating voltage of 0.5–30 kV.
lm and at
Antimicrobial evaluation
Test micro organism strains
Some of these synthesized compounds and ligands used were
screened for their in vitro antimicrobial activities against four hu-
man pathogenic bacterial species [Staphylococcus aureus (ATCC
9144) (G+), Bacillus subtilis (ATCC 6051) (G+), Escherichia coli (ATCC
9637) (Gꢀ) and Pseudomonas aeruguinosa (ATCC 25619) (Gꢀ)] and
two plant fungal species [Aspergillus niger (ATCC 9029) and Tricho-
derma ressie (ATCC 164)] by using the well disc diffusion method
[26]. Chloroamphenicol and terbinafin were used as standard
drugs for the comparison.
Method
The compound was dissolved in DMF, to get 200
solution. Further progressive double dilutions were performed to
obtain the required concentrations of 100 and 50
g mLꢀ1. A
l
g mLꢀ1
Experimental
l
0.5 mL (containing 107 microorganisms per mL) of the each inves-
tigated micro-organisms was added to a sterile nutrient agar
(for bacteria)/dextrose agar (for fungi) medium just before solidifi-
cation, then poured onto sterile petri dishes (9 cm in diameter) and
left to solidify. Using sterile cork borer (6 mm in diameter), three
holes (wells) were made in each dish and then 0.1 mL of tested
Materials and methods
All the experimental manipulations were carried out under
moisture-free conditions. Arsenic compounds being highly toxic
and dangerous in nature, appropriate precautions were taken
throughout all the experimental manipulations. Solvents were
purified by standard methods [22]. Toluene-3,4-dithiol (Alfa Ae-
sar), arsenic trioxide (Fluka) and ligands {benzoic acid, thiobenzoic
acid, anhydrous sodium acetate, thioacetic acid, phenol, thiophe-
nol, sodium salicylate, thio glycolic acid and disodium oxalate
(all Fluka and Merck-Germany)} were used as received without
further purification. Thionyl chloride (Merck) was distilled before
use. Arsenic trichloride was prepared by the reaction of arsenic tri-
oxide and thionyl chloride [23]. Toluene-3,4-dithiolatoarsenic(III)
chloride [24] was prepared by the reaction of arsenic(III) chloride
and toluene-3,4-dithiol in equimolar ratio (1:1) in anhydrous
benzene.
compound dissolved in DMF (50, 100 and 200 l
g mLꢀ1) was
poured into these holes. Finally the dishes were incubated at
37 °C for 24 h for bacteria and at 30 °C for 72 h for fungi, where
clear or inhibition zones were detected around each hole. Inhibi-
tory activity was measured (in mm) as diameter of the inhibition
zones. DMF showed no effect on the organisms tested.
Synthesis of toluene-3,4-dithiolatoarsenic(III) derivatives with oxygen
and sulphur donor ligands
To the solution of toluene-3,4-dithiolatoarsenic(III) chloride
(0.26 gm; 0.99 mmole) in benzene (ꢁ25 ml) was added drop wise
benzene solution (ꢁ25 ml) of benzoic acid (0.12 gm; 0.99 mmole).
The contents were heated under reflux for ꢁ5 hr. and libration of
HCl gas was observed. After cooling, the solvent was removed
under reduced pressure and a light yellow solid product thus
obtained was recrystallized in CH2Cl2. Yield 342 mg; 98%;
M. P. = 60 °C (Scheme A.1).
The solution of toluene-3,4-dithiolatoarsenic(III) chloride
(0.29 gm, 1.12 mmol) in benzene (ꢁ30 ml) was added drop wise
to sodium salicylate (0.17 gm, 1.12 mmol) suspension in benzene
(ꢁ25 ml) in 1:1 molar ratio. The contents were heated under reflux
for ꢁ5 h. Precipitated sodium chloride (0.06 gm) was removed by
filtration. On removing the solvent from the filtrate, yellow semi
solid obtained, was recrystallized from n-hexane. Yield 364 mg;
88%; M.P. = 48 °C (Scheme A.1).
Analytical methods and physical measurements
Arsenic was estimated iodometrically [25] and sulphur was
estimated gravimetrically as barium sulphate [25]. Melting points
were determined on B 10 Tech India Melting Point Apparatus and
are uncorrected. Molecular weights were determined cryoscopical-
ly in benzene. Elemental analysis (carbon and hydrogen) were per-
formed on a Heraeus Carlo Erba 1108 C, H, N analyzer at SAIF, CDRI,
Lucknow, India. The UV spectra were recorded in chloroform solu-
tion at room temperature on a Shimadzu UV-1600 UV–Vis Spectro-
photometer within the range 200–500 nm. Infrared spectra were
recorded in the region 4000–400 cmꢀ1 using a Bruker Vertex mod-
el 70 Spectrophotometer as KBr disc and in the region 600–
50 cmꢀ1 as nujol mull over CsI disks using a Magna-IR Spectropho-
tometer-550 instrument. 1H and 13C NMR Spectra were recorded in
CDCl3 solutions using TMS as an internal indicator on a FT NMR
Spectrometer model Advance-II (Bruker), operated at 300.40 and
All other derivatives were prepared by adopting a similar meth-
od; pertinent analytical and physicochemical data are listed in Ta-
ble A.1.

H.P.S. Chauhan, S. Bhatiya / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
1135
C
H3
C
H3
S
S
S
S
Benzene
NaCl / HCl
As
R
As Cl
NaR/ HR
+
+
Scheme A.1. Reactions of toluene-3,4-dithiolatoarsenic(III) chloride with oxygen and sulphur donor ligands.
Table A.1
Analytical and physicochemical data of toluene-3,4-dithiolatoarsenic(III) derivatives with oxo and thio carboxylic and phenolic ligands.
Compound
no.
Empirical formula and yield
(%)
M.P.
(°C)
Molecular weight found
(Calc.)
Color and state
Analysis (%): found (calculated)
As
S
C
H
1
2
3
C14H11O2S2As98
C14H11O1S3As86
C9H9O2S2As99
C9H9O1S3As94
60
82
–
342(350.28)
362(366.34)
-(288.21)
Light yellow
solid
Pale yellow
solid
yellow semi-
solid
Brown Liquid
Brown solid
Light yellow
solid
21.18(21.39) 18.25(18.30) 47.92(48.00) 3.05(3.16)
20.28(20.45) 26.16(26.25) 45.68(45.90) 3.00(3.03)
25.82(25.99) 22.17(22.25) 37.43(37.51) 3.10(3.15)
4
5
6
–
62
80
300(304.27)
318(322.27)
322(338.33)
24.52(24.62) 31.52(31.61) 35.40(35.53) 2.94(2.98)
23.20(23.25) 19.80(19.90) 48.34(48.45) 3.42(3.44)
22.10(22.14) 28.38(28.43) 46.04(46.15) 3.20(3.28)
C
C
13H11O1S2As99
13H11S3As96
7
8
9
C14H11O3S2As88
C9H9O2S3As98
48
–
64
358(366.28)
310(320.27)
538(546.35)
Paleyellow solid 20.40(20.45) 17.50(17.50) 45.86(45.91) 3.02(3.03)
Yellow liquid
Yellow solid
23.30(23.39) 30.00(30.03) 33.56(33.75) 2.74(2.83)
27.32(27.43) 23.32(23.47) 35.12(35.17) 2.18(2.21)
C
16H12O4S4As292
probably a monodentate behavior of carboxylates ligands with ar-
senic [32–34].
Results and discussion
The infrared spectra of sulphur donor ligands [14,28] complexes
display two characteristic bands at 1635–1750 and 920–960 cmꢀ1
respectively due to C@O and C–S bond stretching vibrations. The
band present in the region 310–320 cmꢀ1 is due to (As–S) stretch-
ing vibration. In addition, the bands appearing in the region 730–
803 cmꢀ1 may be attributed to an asymmetrically trisubstituted
benzene ring.
Syntheses
Toluene-3,4-dithiolatoarsenic(III) derivatives have been synthe-
sized by the reactions of toluene-3,4-dithiolatoarsenic(III) chloride
with oxygen and sulphur donor ligands in 1:1 and 2:1 molar ratio
in refluxing anhydrous benzene for ꢁ5 h (Scheme A.1).
All these synthesized derivatives are yellow, yellow–brown sol-
ids/ liquids. All these derivatives are soluble in common organic
solvents like benzene, chloroform, dichloromethane, dimethyl
formamide, dimethyl sulphoxide etc. and are not soluble in aque-
ous medium. These compounds along with their analytical and
physicochemical data have been summarized in Table A.1.
1H NMR spectra
In all these derivatives a sharp singlet has been observed in the
region 2.28–2.37 d due to ring methyl protons. These derivatives
[12–14,33] also show a sharp singlet in the region 7.14–7.26 d
due to ring C2 proton and two doublets in the region 7.31–7.52 d
and 6.93–6.98 d due to ring C5 and C6 proton respectively. The
methyl group of ligand moieties showed a sharp singlet in the re-
gion 1.56–1.57 d due to CH3 protons. However some complexes
contain phenyl protons in ligands, exhibited signals in the region
at 6.83–8.07 d showing a complex pattern.
Electronic spectra
The electronic spectra of these synthesized [14,27] arsenic com-
pounds exhibit three bands. In all the arsenic derivatives, the
and n–p⁄ transition are due to oxygen and sulphur ligand moieties
and
p⁄ intramolecular charge transfer transitions due to toluene
p–
p⁄
p–
In addition, these compounds also show expected proton reso-
nances due to corresponding carboxylic and phenolic proton of li-
gand moieties (Table A.2).
moieties overlap and exhibit most intense broad band in the range
230–270 nm. The second band appears as a shoulder (260–
290 nm) and is assigned to
p–
p⁄ transition in the C@O (ligand)
group. The third band of low intensity at 290–330 nm is attributed
to n–p⁄ or charge transfer transition due to ligand moiety.
13C NMR spectra
Infra-red spectra
The 13C NMR signals thus obtained are at reported values [12–
14,33] without any appreciable shifts.
The tentative assignments of the important characteristic bands
in IR have been made with the help of earlier publications [14,28–
32]. The bands of medium to strong intensity observed in oxygen
donor complexes in the region 1635–1700 cmꢀ1 and 1260–
1270 cmꢀ1 may be attributed to asymmetric carboxylate anion
and symmetric carboxylate anion stretching vibration of carboxyl-
ate moieties respectively. The asymmetric carboxylate anion
The 13C NMR spectra of all these derivatives exhibit signal in the
region 20.62–21.22 d which is due to ring methyl carbon and in the
range 126.07–126.64 d; 126.49–128.30 d; 127.32–128.58 d;
135.01–136.57 d; 135.65–137.15 d and 139.24–140.51 d due to
ring carbon number C6; C2; C5; C4; C3; and C1 resonances respec-
tively. Methyl carbon of ligand moieties exhibited signal in the re-
gion 16.23–16.95 d. However, some complexes containing phenyl
carbons in ligands also exhibited signals in the same region
(Table A.2).
stretching vibration {
masy. (COO)} is shifted to higher frequency
in all the carboxylates derivatives. This shifting is indicating, most

1136
H.P.S. Chauhan, S. Bhatiya / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
Table A.2
1H and 13C NMR spectral data (d) of toluene-3,4-dithiolatoarsenic(III) compounds with oxygen and sulphur donor ligands.
Com. no.
1
Compound
1H NMR chemical shift (d)
13C NMR chemical shift (d)
2.29, s, 3H (ring CH3)
20.72(ring CH3)
6.97, d, 1H {ring CH(6)}; J = 8.1 Hz
7.18, s, 1H {ring CH(2)}
7.35–8.07, m, 6H {ring CH(5) and C6H5}
126.50 {ring C-6}
127.23 {ring C-2}
127.33 {ring C-5}
128.49 {C6H5–C(3 and 5)}
130.21 {C6H5–C(2 and 6)}
130.86 {C6H5–C(1)}
133.80 {C6H5–C(4)}
136.04 {ring C-4}
136.50 {ring C-3}
140.21 {ring C-1}
180.25 {COO}
2
2.29, s, 3H (ring CH3)
20.67(ring CH3)
6.97, d, 1H {ring CH(6)}; J = 8.1 Hz
7.18, s, 1H {ring CH(2)}
7.38-8.07, m, 6H {ring CH(5) and C6H5}
126.66{ring C-6}
126.79 {C6H5–C(2 and 6)}
127.49 {ring C-2}
128.12 {ring C-5}
128.56 {C6H5–C(3 and 5)}
134.03 {C6H5–C(4)}
135.91 {C6H5–C(1)}
136.57 {ring C-4}
137.00 {ring C-3}
140.51 {ring C-1}
195.36 {COS}
3
4
5
1.56, s, 3H (CH3)
2.34, s, 3H (ring CH3)
6.96, d, 1H {ring CH(6)}; J = 8.1 Hz
7.14, s, 1H {ring CH(2)}
7.51, d, 1H {ring CH(5)}; J = 8.1 Hz
16.23 (CH3)
20.70 (ring CH3)
126.07 {ring C-6}
126.49 {ring C-2}
127.36 {ring C-5}
136.01 {ring C-4}
136.54 {ring C-3}
139.98 {ring C-1}
182.28 {COO}
1.57, s, 3H (CH3)
2.29, s, 3H (ring CH3)
6.94, d, 1H {ring CH(6)}; J = 8.1 Hz
7.26, s, 1H {ring CH(2)}
7.32, d, 1H {ring CH(5)}; J = 8.1 Hz
16.95 (CH3)
20.70 (ring CH3)
126.64 {ring C-6}
128.30 {ring C-2}
128.58 {ring C-5}
135.80 {ring C-4}
137.15 {ring C-3}
139.42 {ring C-1}
162.17 {COS}
2.32, s, 3H (ring CH3)
20.72 (ring CH3)
7.03-7.50, m, 8H {ring CH(2,5 and 6) and C6H5}
115.72 {C6H5- C(2 and 6)}
121.12 {C6H5- C(4)}
126.50 {{ring C-6}
127.23 {{ring C-2}
127.32 {ring C-5}
129.92 {C6H5- C(3 and 5)}
136.06 {ring C-4}
136.50 {ring C-3}
139.73 {ring C-1}
155.21 {C6H5- C(1)}
20.62 (ring CH3)
6
2.28, s, 3H (ring CH3)
6.83–7.49, m,8H {ring CH(2,5 and 6) and C6H5}
126.20 {C6H5- C(4)}
126.64 {ring C-6}
127.03 {ring C-2}
128.48 {(ring C-5) and C6H5- C (3 and 5)}
128.78 {C6H5–C(2 and 6)}
130.22 {C6H5–C(1)}
135.04 {ring C-4}
135.65 {ring C-3}
139.24 {ring C-1}
20.72 (ring CH3)
7
2.37, s, 3H (ring CH3)
6.90–7.93, m, 7H {ring CH(2,5 and 6) and C6H4}
10.46, s, 1H {OH}
111.37 {C6H4–C(2)}
117.80 {C6H4–C(6)}
119.54 {C6H4–C(4)}
126.50 {ring C-6}
127.24 {ring C-2}
127.33 {ring C-5}
130.87 {C6H4–C(5)}
135.01 {ring C-4}
136.88 {ring C-3 and C6H4–C(3)}

H.P.S. Chauhan, S. Bhatiya / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
1137
Table A.2 (continued)
Com. no. Compound
1H NMR chemical shift (d)
13C NMR chemical shift (d)
139.48 {ring C-1}
162.20 {C6H4–C(1)}
180.78 {COO}
8
2.34, s, 3H (ring CH3)
3.83, s, 2H (SCH2)
21.22 {ring CH3}
42.96 {SCH2}
7.03–7.60, m, 3H {ring CH(2,5 and6)}
126.49 {ring C-6}
127.22 {ring C-2}
127.32 {ring C-5}
136.01 {ring C-4}
136.54 {ring C-3}
139.48 {ring C-1}
176.89 {COO}
9
2.34, s, 6H (ring CH3)
7.03–7.49, m, 6H {ring CH(2, 5 and 6)}
20.72 {ring CH3}
126.50 {ring C-6}
127.23 {ring C-2}
127.33 {ring C-5}
136.05 {ring C-4}
136.54 {ring C-3}
140.21 {ring C-1}
176.83 {COO}
Note: s = singlet; d = doublet; m = complex pattern.
Table A.3
Thermal analyses (TGA, DTA and DSC) of toluene-3,4-dithiolatoarsenic(III) thiobenzoate.
Step TGA
DTAb
DSC
Temperature/ 0C
aTemp. range
°C
Total
loss,%
44.36
Different loss, % Found
(Calcd.)
44.36 (42.90)
Remaining fragments
Temp.
°C
272
Type of
reaction
Endo.
I
5–460 A
2-CH2–CH3 + CO + ½
(As2S3)
81.26 Endo., 134.15 Exo., 163.93 Endo., 220
Endo.,
II
460–600 A
66.88
66.88 (66.42)
66.88 (66.42)
½ As2S3
530
Endo.
Total loss,% A = 66.88
Remaining Material (½ As2S3) A = 33.12 (33.58)
a
SC6H3 (CH3) SAsSOCC6H5.
Endo.: endothermic process, exo.: exothermic process.
b
ESI-mass spectra
[M + SC6H3]+, 443.1 (17) [M + C5HS]+, 427.2 (7) [M + C4S]+, 375.1
(5) [M + C2]+, 350 [SC6H3(CH3)SAsOOCC6H5 (M)]+; 319.2 (6) [M–
OCH3]+, 301.1 (16) [M–HOC2H6]+, 283.1 (26) [M–CH6OOCH5]+,
229.7 (9) [M–SCH3(CH3)COOCH5]+, 203.1 (7) [M–SC2H3(CH3)
OOCC2H5]+, 179.0 (65) [M–SC2H3(CH3)OOCC4H5]+, 161.0 (100)
ESI-Mass spectra of two of the complexes, SC6H3(CH3)SAs-
OOCC6H5 and SC6H3(CH3)SAsSOCC6H5 have been recorded. ESI–
Mass spectrometry is one of the most important methods to deter-
mine molecular weight of the complexes [34–36] and to identify
the fragments formed during electrospray ionization, which reveal
composition and properties of the particular moiety of the com-
plexes. Two important peaks were observed in the ESI-Mass spec-
trum: the molecular ion peak, indicating the molecular mass of the
complex, which is weak in the case of the complexes investigated,
and the base peak. The mass spectra of the mixed ligand complexes
of arsenic, antimony and bismuth showed a weak molecular ion
peak, which may be due to a pyrolytic decomposition because of
the relatively high temperature, or due to the fragmentation of
molecular ion in the ionization chamber. Also the relative intensity
of the molecular ion peak decreases as the degree of branching in-
creases in the complex [37].
[M–SC2H3(CH3)OOCC5H5]+, 145.1 (6) [M–SC6H3(CH3)OOCC3H5]+
+
and 117.0 (24) [M–SC6H3(CH3)OOCC5H5]
.
Positive-ion ESI-mass spectra of SC6H3(CH3)SAsSOCC6H5 (M) m/z
(%) [Possible formula of the fragment]: 541.2 (16)
[M + S2OCC6H5]+
485.5 (13) [M + SCC6H5]+, 451.1 (12)
;
[M + CC6H5]+, 435.1 (25) [M + C6]+, 413.4 (16) [M + C4]+, 387.1
(54) [M + C2]+, 365.1 [SC6H3(CH3)SAsSOCC6H5 (M)]+; 360.4 (25)
[M–H5]+, 359.1 (15) [M–H6]+, 297.1 (47) [M–C5H8]+, 274.3 (68)
[M–C7H8]+, 243.1 (18) [M–SC7H8]+, 229.0 (74) [M–SC8H10]+, 202.2
(100) [M–SC10H10]+, 185.0 (34) [M–S2CC8H10]+, 167.0 (19) [M–
S2OCC8H11]+, 153.0 (13) [M–S2OCC9H11
S2OCC13H11]+.
]
and 105.1 (70) [M–
+
We observe weak molecular ion peaks for complexes
SC6H3(CH3)SAsOOCC6H5 and SC6H3(CH3)SAsSOCC6H5 at m/z 350
and m/z 365, respectively. The base peak for complexes, are ob-
served at m/z 161.0 and 202.2 respectively. The ESI-mass spectra
of the complexes are very complex due to the formation of various
unexpected adducts. The possible formulae of the fragments and
their m/z ratios are as follows;
Scanning electron microscopy study and powder x ray diffraction
study [38]
The compound (Fig. A.1) showed different topography and mor-
phology at two different magnifications in which rough texture ap-
pears with grooves and ridges on the surface. The particle size is
found to be in the range from 5 to 20
have agglomerated.
lm. The particle seems to
Positive-ion ESI-Mass spectra of SC6H3(CH3)SAsOOCC6H5 (M) m/z
(%) [Possible formula of the fragment]: 498.5 (3)
[M + SC6H3(CH3)S]+; 479.2 (5) [M + SC6H3(CH3)]+, 461.2 (12)
X-ray diffraction studies help us to understand structural char-
acteristics like crystal lattice, lattice parameters, lattice angle, unit
cell volume and particle size of the complex while SEM studies

1138
H.P.S. Chauhan, S. Bhatiya / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
Fig. A.1. SEM images of toluene-3,4-dithiolatoarsenic(III) thioacetate.
show external morphology contains surface properties thus pow-
der XRD in combination to SEM studies gives characteristic infor-
mation about complex by which may elaborate more about
structural chemistry of the complex. Powder X- ray diffraction pat-
terns for two of the complexes namely toluene-3,4-dithiolatoarse-
nic(III) thiophenolate and toluene-3,4-dithiolatoarsenic(III) oxalate
(Fig. S.1 and 2 respectively), were recorded and important struc-
tural information have been shown in Tables S.1 and S.2. Average
particle size of the synthesized complexes was determined with
the help of the Scherrer formula, [38] in which particle size D is de-
fined as 0.9k/B coshb, where 0.9 = constant, k = wavelength,
B = angular width and hb = diffraction angle. Toluene-3,4-dithiolat-
oarsenic(III) thiophenolate exhibited tetragonal crystal system
having average particle size of the complex 1.56 nm, and exhibited
two phase material characteristics which is little more complex
than single phase material indicating formation of mixed ligand
complex. Toluene-3,4-dithiolatoarsenic(III) oxalate complex
showed monoclinic crystal system strongly supporting distorted
geometry of the complex having average particle size 1.62 nm
and similar to earlier one it also has two phase material character-
istics. Peaks having important characteristic information have been
identified with the help of standard diffraction card JCPDS 48–
2318, 20–1149, 36–1909 and 14–0907 and indicate formation of
nanosized, polycrystalline, two phase and low symmetry com-
plexes. The largest relative deviation between the calculated and
experimental d values was nearly equal to one, which indicates
that both the synthesized complexes are multiphase complexes.
Interplanar d spacing and unit cell volume of the synthesized com-
plexes were calculated by the formulae:
or time indicates formation of metal sulfide as a final decomposi-
tion product. The complex SC6H3(CH3)SAsSOCPh showed double
stage weight loss in inert atmosphere. First decomposition oc-
curred within a range of 50–460 °C, in which most of the organic
part of the product has volatilized and we found ½As2S3 and some
organic moieties as a remaining fragment. In final step of weight
loss within a range of 460–600 °C, remaining volatile part further
decomposed and we get pure ½As2S3 which is confirmed by
remaining material percentage 33.12(33.58). The compound finally
yields highly pure (As2S3) probably of nano size at the end
(Fig. S.1).
In addition to TGA analysis, DTA studies (Fig. S.3) are helpful
in order to determine type of reaction which occurs during
decomposition process. In DTA curve, decomposition of product
is represented as endothermic peaks at 272 °C and °C for
SC6H3(CH3)SAsSOCPh.
The DSC data of SC6H3(CH3)SAsSOCPh showed (Fig. S.4) an
endothermic change at 81.26 °C (melting point of the complex),
an exothermic change observed at 134 °C, a broad endothermic
change at 163.93 °C and followed by a broad endothermic change
at 210–240 °C.
Antimicrobial activity
The metal precursor, free ligands and their arsenic(III) com-
plexes [39] were screened to evaluate their antimicrobial activity
in vitro against four human pathogenic bacterial species [Staphylo-
coccus aureus (ATCC 9144) (G+), Bacillus subtilis (ATCC 6051) (G+),
Escherichia coli (ATCC 9637) (G–) and Pseudomonas aeruguinosa
(ATCC 25619) (G–)] and two fungal species [A. niger (ATCC 9029)
and Trichoderma ressie (ATCC 164)] at three different concentra-
!
!
1
d2
h2 þ k2
l2
c2
¼
þ
tions (50, 100 and 200 l
g mLꢀ1). Chloroamphenicol and terbinafin
were used as standard and were compared with free ligands and
their arsenic(III) complexes.
a2
V = a2c; and
!
The impact of the central metal atom of the compounds was
found in the antimicrobial activity against the tested bacterial
and fungal species. The results obtained by disc diffusion method
indicate that the coordination compounds have enhanced activity
compared to the ligands, which indicates that the coordinated
As(III) atom increases the antimicrobial effects. The effect is as ex-
pected, proportional to the concentration of the compounds.
Comparison of the antimicrobial activities of the free ligands
and their synthesized As(III) compounds with Chloroamphenicol
(standard antibacterial drug) and terbinafin (standard antifungal
drug) exhibit the following results:
1
1
h2 k2sin2b l2 2hl cos b
¼
þ
þ
ꢀ
c2
d2 sin2b
b2
a2
ac
V = abcsinb.
Thermal studies
The mass losses, temperature ranges and final decomposition
products for toluene-3,4-dithiolatoarsenic(III) thiobenzoate com-
plex are presented in Table A.3. The results show good agreement
with theoretical formula as suggested from the analytical data.
Thermo gravimetric analysis of compound in which we analyze a
change in the weight of the substance as a function of temperature
(i) The results showed that the arsenic(III) derivatives are
exhibiting higher antibacterial and antifungal activity than

H.P.S. Chauhan, S. Bhatiya / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 97 (2012) 1133–1139
1139
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.saa.2012.07.086.
References
[1] B.W. Wenclawiak, S. Uttich, H.J. Deiseroth, D. Schmitz, Inorg. Chimica Acta 348
(2003) 1–7.
Fig. A.2. Proposed structure of the derivatives.
[2] H.D. Yin, J. Zhai, Y.Y. Sun, D.Q. Wang, Polyhedron 27 (2008) 663–670.
[3] S. Maheshwari, J.E. Drake, K. Kori, M.E. Light, R. Ratnani, Polyhedron 28 (2009)
689–694.
[4] A.L. Bingham, J.E. Drake, M.B. Hursthouse, M.E. Light, M. Nirwan, R. Ratnani,
Polyhedron 26 (2007) 2672–2678.
[5] H.P.S. Chauhan, U.P. Singh, Appl. Organomet. Chem. 21 (2007) 880–889.
[6] A.K. Jain, R. Bohra, Appl. Organomet. Chem. 20 (2006) 411–415.
[7] A. Gupta, R.K. Sharma, R. Bohra, V.K. Jain, J.E. Drake, M.B. Hursthouse, M.E.
Light, J. Organomet. Chem. 678 (2003) 122–127.
[8] D. Barreca, A. Gasparotto, C. Maragno, R. Seraglia, E. Tondello, A. Venzo, V.
Krishnan, H. Bertagnolli, Appl. Organomet. Chem. 19 (2005) 1002–1009.
[9] T.A. Shaikh, S. Parkin, D.A. Atwood, J. Organomet. Chem. 691 (2006) 4167–
4171.
[10] H.P.S. Chauhan, N.M. Shaik, U.P. Singh, S. Mathur, M. Zimmer, Main Group Met.
Chem. 30 (2007) 269–278.
[11] H.P.S. Chauhan, U.P. Singh, N.M. Shaik, S. Mathur, V. Huch, Polyhedron 25
(2006) 2841–2847.
[12] H.P.S. Chauhan, K. Kori, N.M. Shaik, S. Mathur, V. Huch, Polyhedron 24 (2005)
89–95.
[13] H.P.S. Chauhan, K. Kori, Phosphorus, Sulfur Silicon Relat. Elem. 178 (2003)
1815–1823.
the free ligands by which these have been synthesized. It is
noticeable here that bacteria and fungi resist to the free car-
boxylic and phenolic ligands. It may be concluded that the
free ligands and arsenic complexes inhibit the growth of
bacteria to a greater extent as the concentration is increased.
(ii) All the synthesized arsenic(III) compounds showed a greater
or equal activity against bacterial and fungal species than
the standard Chloroamphenicol and terbinafin.
(iii) Compounds 1,5,6 showed the modest activity against all the
microbial strains.The antibacterial activity of a common
standard antibiotic. Chloroamphenicol was also recorded
using the same procedure as above at the same concentra-
tion and solvent. The% Activity Index [40] for the complex
was calculated by the formula as under:
Zone of inhibition by test compoundðdiameterÞ
%Activity Index ¼
[14] H.P.S. Chauhan, S. Bhatiya, A. Bakshi, Spectrochim. Acta
Spectrosc. 74 (2009) 67–73.
A Mol. Biomol.
Zone of inhibition by standard compoundðdiameterÞ
[15] M.K. Rauf, M.A. Saeed, Imtiaz-ud-din, M. Bolte, A. Badshah, B. Mirza, J.
Organomet. Chem. 693 (2008) 3043–3048.
[16] P.J. Dilda, P.J. Hogg, Cancer Treatment Rev. 33 (2007) 542–564.
[17] S.J. Ralph, Met-Based Drugs (2008) 1–13. Article ID 260146.
[18] W.H.C. Rueggeberg, A. Ginsberg, W.A. Cook, J. Am. Chem. Soc. 68 (1946) 1860–
1862.
ꢂ 100
Conclusion
The mixed toluene-3,4-dithiolatoarsenic(III) complexes with
oxygen and sulphur ligands were synthesized and tentatively
structurally characterized, although without actual single X-ray
crystal structure analysis of at least one of the product, it is difficult
to assign the actual structure of the compounds. However, on the
basis of above spectral data, it may be concluded tentatively that
these ligands behave as monodentate mode of attachment to the
metal, thus leading to a three coordinated distorted pyramidal
geometry, with a stereo chemically active lone pair of electrons
(Fig. A.2). Presence of lone pair has also been supported by crystal
system obtained with the help of powder X-ray diffraction study;
tetrahedral and monoclinic system indicated lower symmetry of
the complex and two phase material system strongly supports
the formation of mixed ligand compounds. Final product of the
thermal decomposition is found to be As2S3 most probably that
of nano size.We may also conclude that some of the free ligands
and their arsenic(III) complexes exhibited greater or comparable
antimicrobial effects in comparison to some of the investigated
antibiotics.
[19] W.J. Vickaryous, E.R. Healey, O.B. Berryman, D.W. Johnson, Inorg. Chem. 44
(2005) 9247–9252.
[20] W.J. Vickaryous, R. Herges, D.W. Johnson, Angew. Chem. Int. Ed. 43 (2004)
5831–5833.
[21] S.S. Garje, V.K. Jain, Coord. Chem. Rev. 236 (2003) 35–56.
[22] J.A. Riddick, W.B. Bunger, Techniques of Chemistry (Organic Solvents), 3rd ed.
Vol. 2., Wiley Interscience, New York, 1970.
[23] S.K. Pandey, A. Steiner, H.W. Roesky, Inorg. Synth. 31 (1997) 148–150.
[24] H.P.S. Chauhan, K. Kori, N.M. Shaik, Main Group Met. Chem. 25 (2002) 659–
662.
[25] A.I. Vogel, Quantitative Inorganic Analysis, 3rd ed., Longman, London, 1961.
[26] H.P.S. Chauhan, N.M. Shaik, J. Inorg. Biochem. 99 (2005) 538–545.
[27] I.A.W. Abdulaziz, A.A.F. Khalid, M.A. Saad, H.M. Mohsen, M.M. Refaat,
Spectrosc. Lett. 34 (2001) 737–743.
[28] S. Bhattacharya, Spectrochim. Acta A Mol. Biomol. Spectrosc. 61 (2005) 3145–
3149.
[29] Y. Ma, J.S. Li, Z. Xuan, R. Liu, J. Organomet. Chem. 620 (2001) 235–242.
[30] K.R. Chaudhari, V.K. Jain, V.S. Sagoria, E.R.T. Tiekink, J. Organomet. Chem. 692
(2007) 4928–4932.
[31] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination
Compounds, Part B, 5th ed., John Wiley & Sons, New York, 1997.
[32] D.N. Sathyanarayana, Vibrational Spectroscopy Theory and Applications, 2nd
ed., New Age Internat. Lim. Pub., New Delhi, 2005.
[33] R.M. Silverstein, G.C. Bassler, T.C. Morrill, Spectrometric Identification of
Organic Compounds, 4th ed., John Wiley & Sons, New York, 1981.
ˇ
[34] T.S.B. Baul, K.S. Singh, M. Holcapek, R. Jirásko, E. Rivarola, A. Linden, J.
Acknowledgement
Organomet. Chem. 690 (2005) 4232–4242.
ˇ
ˇ
ˇ ˇ
ˇ
[35] L. Machuca, L. Dostál, R. Jambor, K. Handlír, R. Jirásko, A. Ru˚ zicka, I. Císarová, J.
ˇ
Holecek, J. Organomet. Chem. 692 (2007) 3969–3975.
Financial assistance from the University Grants Commission,
New Delhi is gratefully acknowledged. We are thankful to SAIF,
CDRI, Lucknow {for elemental analyses (C and H)}, SAIF, IIT, Bom-
bay (for Far- FTIR measurement), IUC-DAE, Indore (for Powder
XRD studies) and CSMCRI, Bhavnagar (for TGA and DTA studies).
We are also thankful to School of Studies in Botany, Vikram Univer-
sity, Ujjain for providing the necessary laboratory facilities for
antimicrobial studies.
[36] D.F. Schoener, M.A. Olsen, P.G. Cummings, C. Basic, J. Mass Spectrom. 34 (1999)
1069–1078.
[37] C.A. Tsipis, G.E. Manoussakis, Inorg. Chim. Acta 18 (1976) 35–45.
[38] B. D. Cullity, Department of Metallurgical Enginnering and Material Science.
Addison-Wesley Publishing Company, Reading, MA, USA, 1958.
[39] Konidaris, C.P. Raptopoulou, V. Psycharis, S.P. Perlepes, E.M. Zoupa, T.C.
Stamatatos, Bioinorg. Chem. App. (2010), http://dx.doi.org/10.1155/2010/
159656. Article ID 159656.
[40] V.P. Singh, A. Katiyar, S. Singh, Biometals 21 (2008) 491–501.